核融合反応の燃料となるリチウムケイ酸塩の研究(Studying Lithium Silicates to Fuel Fusion Reactions)

2024-09-10 パシフィック・ノースウェスト国立研究所(PNNL)

＜関連情報＞

• https://www.pnnl.gov/publications/studying-lithium-silicates-fuel-fusion-reactions
• https://www.sciencedirect.com/science/article/abs/pii/S002231152300051X?via%3Dihub

核融合ブランケット応用のためのリチウムケイ酸塩のイオン照射研究 Ion irradiation study of lithium silicates for fusion blanket applications

Weilin Jiang, Libor Kovarik, Mark G. Wirth, Zihua Zhu, Nathan L. Canfield, Lorraine M. Seymour, Larry M. Bagaasen, Mark E. Bowden, Tamas Varga, Nicole R. Overman, Zhihan Hu, Lin Shao, David J. Senor
Journal of Nuclear Materials  Available: online 15 January 2023
DOI:https://doi.org/10.1016/j.jnucmat.2023.154281

Abstract

This study reports on the ion-irradiation induced microstructural and compositional evolutions, behavior of deuterium release, and lithium loss from lithium silicates. Pellets of biphasic Li₄SiO₄ and Li₂SiO₃ were fabricated using hot pressing of milled powders. Sequential irradiation with Si⁺, He⁺ and D⁺ ions was performed up to 773 K to emulate one-year ⁶Li burnup in ⁶Li₄SiO₄ inside the SlimCS DEMO. Crystalline Li₄SiO₄ phase was not observed in the irradiated depth region in this study. In spite of full amorphization in the near-surface region, Li₂SiO₃ irradiated to a high dose at 773 K remained crystalline in the damage peak region, suggesting that Li₂SiO₃ is more irradiation resistant to amorphization than Li₄SiO₄. Radiolysis may be primarily responsible for the silicate decomposition and amorphization. Data from this study also show that D release from the pellet is very efficient during ion irradiation at 773 K, which is accompanied with a significant Li loss. Thermal annealing for 10 min at 773 K for the room-temperature irradiated pellet leads to a nearly complete D release without an observable Li loss. A concept of Ni coating on tritium breeder materials is discussed with supporting data to minimize Li loss without a significant impact on tritium diffusion and release.